Uprated heater for Morris Minor

I've made a bit of progress on the heater I'm building for my Morris Minor, but hit a snag too. I had some difficulty getting hold of a sheet of new steel, so I thought I'd use a set of scrap 1mm steel shelves that were fly-tipped near my office instead. In hindsight this was a mistake.

I dismantled them, carried them home on the bus, cleaned the ingrained gunge off using caustic soda and a wire brush (I suspect a local takeway dumped them because a health inspector was coming round), bashed the folded edges flat, marked out the panels, roughly cut them out using a pneumatic nibbler (unfortunately the compressor at home can only supply enough air to power it for about ten seconds every couple of minutes, but it was still easier than doing it by hand with a pair of tin snips), cleaned up the edges with a hand file, and made the folds by clamping along the fold line in the jaws of a cheap workmate clone and bashing with a mallet. At this stage of the process I was feeling quite proud of what I'd achieved so far as it's the first time I've fabricated something this complicated from sheet metal and nothing major had gone wrong yet.

This photo shows roughly how the matrix and blower will fit inside. The box is quite big compared to a standard heater, but it's a snug fit inside even so. There's going to be a frame in the bottom half that the blower mounts to with a sort of "diaphragm" on the top which seals the bottom half from the top half:

Here's a dummy build of the outer panels. There are some more holes to cut out for the water and demister pipes yet, and there'll eventually be a flap to control the front vent:

Then it was time to break out the welder. The white paint proved to be very tough plasticky stuff (presumably some kind of two-pack) that was very difficult to sand off, so I only did a narrow area where the welds were going. Unfortunately the welding proved very difficult. The weld pool didn't seem to want to form properly, and every time I fired an arc up a wide area of paint around it and on the back of the sheet burned off, and huge plumes of noxious white smoke poured off. I wound up going outside, taking a breath, coming back in, welding for a few seconds with my breath held, then going back outside to breathe and wait for the smoke to blow away. I tried a couple of times to sand more paint off around the weld area, but it didn't seem to help. I tried to use the "thin metal technique" but I couldn't get the bursts to join up and I ended up with dozens of individual tacks instead.

Tonight I decided to solve the paint problem by removing it all with chemical stripper. Once I'd done that it became obvious what the main problem had been all along - the metal is galvanized under the paint! Never having tried to weld galvanized steel before I hadn't recognised the symptoms and put the difficulty in getting a good weld and the plumes of smoke down to lack of skill and not removing sufficient paint. I added a couple more tacks and that confirmed it - even with no paint left it was still producing plumes of white smoke and leaving white sooty deposits behind. Here's a picture of the result:

I guess the only thing I can do next, other than getting hold of some non-coated steel and starting again from scratch, is to spend ages sanding the zinc off the edges where I'm going to be welding the front and top to the main body of the unit

Yes I also have did mad things like that too!. Sometimes for stuff like that a bit of thin angle or a section bent to angle and rivetted in is as good. Stripped some bits off wifes dishwasher last week and some of the metal by the time the powdercoating etc was stripped back it was too thin for purpose I had in miind
Heater on Moggy is decent as I remember. It looks better than my old Landy heaters. Really better welding any Galvy stuff outside if conditions permit. Even after cleaning room for a bead you still get fumes and garage is filled. We shouldn`t do it as it`s deadly!!
Alex

My previous Moggy had the later (rectangular) type of heater and I didn't find it all that wonderful, even after flushing the system several times. It may have been knackered though. My 1969 Series 2A Land Rover had the small flat recirculating type of heater and it seemed to put more heat out than the one in my old Moggy, though still nothing like as good as the heater in a modern car. My current Moggy had the early snail-shell type heater when I got it, but the matrix was rotten and they're not really practical to repair because of the weird toroidal crimped and soldered copper and steel construction (I tried and failed). From what I've heard, even when they're working properly they're pretty poor at demisting, which is important to me as I intend to use the car for commuting to work all year round. Fitting a better heater from a Mini or something is quite a common upgrade, but they can be a bit hard to find now (not many Minis left in the scrapyards), so I decided to take it a step further and build my own heater using a powerful blower and more efficient matrix from modern cars. Admittedly rather a lot of effort to go to to get a better heater, but it's an interesting project to learn about sheet metal fabrication anyway.

Re the fumes: I probably wouldn't have started using this steel if I'd realised it was galvanized, but I was working under the mistaken assumption that manufacturers of cheap pressed steel shelves wouldn't go to the expense of both galvanizing and painting them. I'll do any more welding on it outside if possible and be careful not to breathe the fumes.

Troopers certainly do, mines a MK1 and its rotting at light speed. The rear floor has multiple patches and the rear crossmember has been replaced and I spent several weeks repairing the chassis over the rear wheels for the MoT including new bumpstop mounts and a new body mount.

Troopers certainly do, mines a MK1 and its rotting at light speed. The rear floor has multiple patches and the rear crossmember has been replaced and I spent several weeks repairing the chassis over the rear wheels for the MoT including new bumpstop mounts and a new body mount.

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hi
i use a mini heater for my morris minor they say the core of the
heater is bigger
andy

Troopers certainly do, mines a MK1 and its rotting at light speed. The rear floor has multiple patches and the rear crossmember has been replaced and I spent several weeks repairing the chassis over the rear wheels for the MoT including new bumpstop mounts and a new body mount.

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Yeah course they do mate. I`ve chased some rust on my Patrol too . Got it tickety at the mo but as you know it`s a bit of work. Discoverys and Landys aint no better at avoiding it.
Alex

thanks for the answer, friends traveller had a single alloy (modern) fitted a quick look at the back of the wheel et35 offset and 100 marked in another area which i took to be the pcd but 4"=101.6mm not 100

I don't know what you are using to sand off the paint, but I'm assuming an angle grinder?

Two things that are very effective, stripping discs which are a thick mesh disc and abrasive impregnated. Great for paint stripping as there is little or no clogging, it will also remove rust and probably galvanising. Frost sell them as do engineering factors\merchants.
The second one is abrasive flap discs, they are very good for fine finishing or removing galvanising etc. They last for ages, which sanding discs do not.